1. Field of the Invention
The present invention relates to a pyrolyzed coal quencher which cools coal after pyrolyzing the coal, a coal upgrade plant, and a method for cooling pyrolyzed coal.
2. Description of Related Art
Since low ranking coal such as sub-bituminous coal and lignite has a lower carbonization degree and a higher water content than high ranking coal, a calorific value per unit weight is lower. However, since there are abundant deposits of low ranking coal, the low ranking coal is desired to be effectively used. Thus, various coal upgrading techniques have been studied in which the calorific value of the low ranking coal is increased by performing pyrolysis after drying the low ranking coal, and upgraded coal is deactivated so as to prevent spontaneous combustion during transportation or storage (e.g., Japanese Unexamined Patent Application, Publication No. 2014-31462 (hereinafter referred to as JPA 2014-31462)).
JPA 2014-31462 discloses that, after coal is pyrolyzed, the pyrolyzed coal is showered with cooling water to be cooled to about 50° C. to 60° C. at the time of cooling.
However, when the pyrolyzed coal is showered with cooling water and cooled to a condensation temperature of water or less, condensed water (drain water) is generated, and the pyrolyzed coal is exposed to the condensed water. In this case, it becomes difficult to adjust the pyrolyzed coal to a desired water content.
Since the pyrolyzed coal possibly generates heat to be ignited by a hydration reaction during storage, it is preferable to previously adjust the water content of the pyrolyzed coal to a water content in equilibrium with a storage environment.
Since the pyrolyzed coal obtained after the pyrolysis has a temperature of 300° C. or more to 500° C. or less, and a volatile content such as tar is generated by thermal decomposition, it is desirable to promptly cool the pyrolyzed coal in a quencher.
The present invention has been made in view of such circumstances, and an object thereof is to provide a pyrolyzed coal quencher, a coal upgrade plant, and a method for cooling pyrolyzed coal capable of promptly cooling pyrolyzed coal, and adjusting the pyrolyzed coal to a desired water content.